A report by the US Geological Survey indicates that glaciers in Glacier National Park, Montana, are shrinking. Recent estimates indicate the area covered by glaciers has decreased from over $25.5 \ \mbox{km}^2$ in 1850 to about $16.5 \ \mbox{km}^2$ in 1995. Let $A = f(t)$ give the area (in square km) $t$ years after 2000, and assume $f(t) = 16.2 - 0.062t$.

a) Find and explain the meaning of the slope. Which statement best explains its significance?
A. The area covered by glaciers is decreasing by $62,000 \ \mbox{m}^2$ every year.
B. The total area covered by glaciers decreased by $16.2 \ \mbox{km}^2$ from 1850 to 2000.
C. The area covered by glaciers is decreasing by $62 \ \mbox{m}^2$   every year.
D. The total area covered by glaciers is increasing by $0.062 \ \mbox{km}^2$ every year.
E. The area covered by glaciers is decreasing by $16.2 \ \mbox{km}^2$ every year.
F. None of the above

b) Find and explain the meaning of the $A$-intercept. Which statement best explains its significance?
A. The total area covered by glaciers decreased by $16.2 \ \mbox{km}^2$ from 1850 to 2000.
B. The area covered by glaciers in 2000 was $16.2 \ \mbox{km}^2$.
C. The total area covered by glaciers will decrease by $0.062 \ \mbox{km}^2$   from 2000 to 2001.
D. The area covered by glaciers is decreasing by $16.2 \ \mbox{km}^2$ every year.
E. The area covered by glaciers in 2000 was $0.062 \ \mbox{km}^2$ .
F. None of the above

c) For both expressions listed below, enter the letter A-E of the statement which best explains their practical meaning. There are extra, unused statements.

 1. If $f(t) = 9$, then $t$ is
 2. $f( 9 )$ is

A. How much area (in $\mbox{km}^2$) will be covered by glaciers in 9 years.
B. The number of years after 2000 that the amount of glacier area that has disappeared is $9 \ \mbox{km}^2$.
C. The amount of glacier area (in $\mbox{km}^2$) that disappears in 9 years.
D. The number of years after 2000 that the total area covered by glaciers will be $9 \ \mbox{km}^2$.
E. How much area (in $\mbox{km}^2$) will be covered by glaciers in 2009.

d) Evaluate $f( 9 ) =$

e) How much glacier area disappears in 9 years? $\mbox{km}^2$

f) Solve $f(t) = 9$ . $t =$ (round your answer to one decimal place)